Office chair



FIG. 1 is a perspective view of an office chair showing my design;

FIG. 2 is a front view thereof;

FIG. 3 is a back view thereof;

FIG. 4 is a left side view thereof;

FIG. 5 is a right side view thereof;

FIG. 6 is a top view thereof; and,

FIG. 7 is a bottom view thereof.

The broken lines shown in the drawings depict portions of the office chair in which the design is embodied that form no part of the claimed design. 

CLAIM The ornamental design for an office chair, as shown and described. 